Intel® 7500 Chipset Thermal/Mechanical Design Guidelines March 2010 Reference Number: 322825-001
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Contents 1 Introduction .............................................................................................................. 7 1.1 Design Flow ........................................................................................................ 7 1.2 Definition of Terms .............................................................................................. 8 1.3 Reference Documents ..........................................................................................
Figures 1-1 2-1 2-2 2-3 2-4 5-1 5-2 5-3 6-1 Thermal Design Process....................................................................................... 7 IOH Package Dimensions (Top View) ..................................................................... 9 IOH Package Dimensions (Bottom View) ...............................................................10 IOH Package Drawing.........................................................................................
Tables 2-1 2-2 3-1 3-2 6-1 6-2 6-3 6-4 6-5 7-1 7-2 7-3 8-1 B-1 Solder Ball Composition on Intel® 7500 chipset ...................................................... 9 Pre-Load Requirements ...................................................................................... 13 Intel® 7500 Chipset Thermal Design Power .......................................................... 15 Intel 7500 Chipset Thermal Specification and Tcontrol ............................................
Revision History Document Number 322825-001 Description • Initial release of the document.
Introduction 1 Introduction The goals of this document are to: • Outline the thermal and mechanical operating limits and specifications for the Intel® 7500 chipset. • Describe reference thermal solutions that meet the specifications of the Intel 7500 chipset. Properly designed thermal solutions provide adequate cooling to maintain the Intel 7500 chipset case temperatures at or below thermal specifications.
Introduction 1.2 1.3 Definition of Terms FC-BGA Flip Chip Ball Grid Array. A package type defined by a plastic substrate where a die is mounted using an underfill C4 (Controlled Collapse Chip Connection) attach style. The primary electrical interface is an array of solder balls attached to the substrate opposite the die. Note that the device arrives at the customer with solder balls attached. BLT Bond Line Thickness.
Packaging Technology 2 Packaging Technology The Intel 7500 chipset component uses a 37.5 mm, 8-layer flip chip ball grid array (FC-BGA) package (see Figure 2-1, Figure 2-2, and Figure 2-3). Solder Ball composition on IOH is SAC 405 with the following percentage: Table 2-1. Solder Ball Composition on Intel® 7500 chipset Composition Ag Figure 2-1. Percentage 4% Cu 0.5% Sn 95.5% IOH Package Dimensions (Top View) Handling Exclusion Area 10.6 mm 13.8 mm. Die 37.5 mm. 37.5 mm.
Packaging Technology Figure 2-2. IOH Package Dimensions (Bottom View) AT AR AP AN AM AL AK 35.56 35X 1.016 AJ AH AG AF AE AD AC AB AA Y W V U T R P N M L K J H G F E D C B A 1 3 2 5 4 7 6 9 8 11 10 13 12 15 14 17 16 19 18 21 20 23 22 25 24 27 26 29 28 31 30 33 32 35 34 36 Notes: 1. All dimensions are in millimeters. 2. All dimensions and tolerances conform to ANSI Y14.5M-1994.
Packaging Technology Figure 2-3.
Packaging Technology 2.1 Non-Critical to Function Solder Joints Figure 2-4. Non-Critical to Function Solder Joints AT AR AP AN AM AL AK AJ AH AG AF AE AD AC AB AA Y W V U T P R N M L K J H G F E D C B A 1 3 2 5 4 7 6 9 8 11 13 15 17 19 21 23 25 27 29 31 33 35 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Intel has defined selected solder joints of the IOH as non-critical to function (NCTF) when evaluating package solder joints post environmental testing.
Packaging Technology 2.2 Package Mechanical Requirements The Intel 7500 chipset package has a bare die that is capable of sustaining a maximum static normal load of 15 lbf (67N). These mechanical load limits must not be exceeded during heatsink installation, mechanical stress testing, standard shipping conditions, and/or any other use condition. Table 2-2. Pre-Load Requirements Load Value Maximum Static Normal Load 15 lbf Minimum Preload for thermals 8.
Packaging Technology 14 Intel® 7500 Chipset Thermal Mechanical Design Guide
Thermal Specifications 3 Thermal Specifications 3.1 Thermal Design Power (TDP) Analysis indicates that real applications are unlikely to cause the IOH component to consume maximum power dissipation for sustained time periods. Therefore, in order to arrive at a more realistic power level for thermal design purposes, Intel characterizes power consumption based on known platform benchmark applications. The resulting power consumption is referred to as the Thermal Design Power (TDP).
Thermal Specifications TSTHRHI is used to determine throttling point as the temperature increases, and the threshold TSFSC is an offset between the throttling point and the fan speed control point. Threshold TSFSC value is 3. The Tcontrol of 92 °C is a conceptual threshold value to be compared against the thermal sensor reading. When TSFSC > 3, which means IOH thermal sensor reading is less than Tcontrol of 92 °C, system can run under acoustic condition.
Thermal Simulation 4 Thermal Simulation Intel provides thermal simulation models of the Intel 7500 chipset and associated users’ guides to aid system designers in simulating, analyzing, and optimizing their thermal solutions in an integrated, system-level environment. The models are for use with the commercially available Computational Fluid Dynamics (CFD)-based thermal analysis tool FLOTHERM* (version 5.1 or higher) by Flomerics, Inc.
Thermal Simulation 18 Intel® 7500 Chipset Thermal Mechanical Design Guide
Thermal Metrology 5 Thermal Metrology The system designer must make temperature measurements to accurately determine the thermal performance of the system. Intel has established guidelines for proper techniques to measure the IOH die temperatures. Section 5.1 provides guidelines on how to accurately measure the IOH die temperatures. Section 5.1.1 contains information on running an application program that will emulate anticipated maximum thermal design power.
Thermal Metrology Figure 5-1. Thermal Solution Decision Flowchart Start Attach device to board using normal reflow process. Figure 5-2. Attach thermocouples using recommended metrology. Setup the system in the desired configuration. Run the Power program and monitor the device die temperature. Select Heatsink Heatsink Required Tdie > Specification? No End Yes Zero Degree Angle Attach Heatsink Modifications NOTE: Not to scale.
Thermal Metrology Figure 5-3. Zero Degree Angle Attach Methodology (Top View) Die Thermocouple Wire Cement + Thermocouple Bead Substrate NOTE: Not to scale.
Thermal Metrology 22 Intel® 7500 Chipset Thermal Mechanical Design Guide
Reference Thermal Solution 6 Reference Thermal Solution Intel has developed reference thermal solutions to meet the cooling needs of the Intel 7500 chipset under operating environments and specifications defined in this document. This section describes the overall requirements for the tall torsional clip heatsink reference thermal solution including critical-to-function dimensions, operating environment, and validation criteria.
Reference Thermal Solution 6.2 Heatsink Performance Figure 6-1 depicts the simulated thermal performance of the reference thermal solution versus approach air velocity. Since this data was modeled at sea level, a correction factor would be required to estimate thermal performance at other altitudes. The following equation can be used to correct any altitude: ca = , and + Q alt – alt – -----o can be obtained from Figure 6-1. Q - “velocity through HS fin area (m/s)”.
Reference Thermal Solution 6.3 Mechanical Design Envelope While each design may have unique mechanical volume and height restrictions or implementation requirements, the height, width, and depth constraints typically placed on the Intel 7500 chipset thermal solution are shown in Figure 6-2. When using heatsinks that extend beyond the IOH reference heatsink envelope shown in Figure 6-2, any motherboard components placed between the heatsink and motherboard cannot exceed 1.60 mm (0.063 in.) in height.
Reference Thermal Solution 6.5 Tall Torsional Clip Heatsink Thermal Solution Assembly The reference thermal solution for the IOH is a passive extruded heatsink with thermal interface. It is attached using a clip with each end hooked through an anchor soldered to the board. Figure 6-5 shows the reference thermal solution assembly and associated components. Full mechanical drawings of the thermal solution assembly and the heatsink clip are provided in Appendix B.
Reference Thermal Solution Figure 6-4.
Reference Thermal Solution 6.5.1 Heatsink Orientation Since this solution is based on a unidirectional heatsink, mean airflow direction must be aligned with the direction of the heatsink fins. Figure 6-5. Tall Torsional Clip Heatsink Assembly Assembly: E12030-007 D79046-004 E12029-001 TIM 6.5.2 Extruded Heatsink Profiles The reference thermal solution uses an extruded heatsink for cooling the IOH. Figure 6-6 shows the heatsink profile. Appendix A lists a supplier for this extruded heatsink.
Reference Thermal Solution 6.5.4.1 Effect of Pressure on TIM Performance As mechanical pressure increases on the TIM, the thermal resistance of the TIM decreases. This phenomenon is due to the decrease of the bond line thickness (BLT). BLT is the final settled thickness of the thermal interface material after installation of heatsink. The effect of pressure on the thermal resistance of the Honeywell PCM45 F TIM is shown in Table 6-2.
Reference Thermal Solution Figure 6-6. Tall Torsional Clip Heatsink Extrusion Profile 6.5.6 Clip Retention Anchors For Intel 7500 chipset based platforms that have very limited board space, a clip retention anchor has been developed to minimize the impact of clip retention on the board. It is based on a standard three-pin jumper and is soldered to the board like any common through-hole header. A new anchor design is available with 45° bent leads to increase the anchor attach reliability over time.
Reference Thermal Solution Figure 6-7. Anchors for Intel 7500 Chipset Tall and Short Heatsink Retention Anchors forces contacting points Wave Soldering Junctions Table 6-4. Anchor Bend Angle and Maximum Pullout force as a Function of Board Thickness Intel Part Number A13494-008 6.6 Anchors pins Foxconn Part Number MB thickness (Inches) Anchor bend angle (degrees) Max THM pullout force for each anchor HB9703E-DW 0.062 45 10lbf HB9703E-M3W 0.
Reference Thermal Solution 32 Intel® 7500 Chipset Thermal Mechanical Design Guide
Reference Thermal Solution 2 7 Reference Thermal Solution 2 Intel has developed two different reference thermal solutions to meet the cooling needs of the Intel 7500 chipset under operating environments and specifications defined in this document. An alternative design that meets the Intel 7500 chipset thermal performance target is short heatsink thermal solution.
Reference Thermal Solution 2 Figure 7-1. Short Torsional Clip Heatsink Measured Thermal Performance versus Approach Velocity Note: Assumed 20.5% power through board at high fan speed and 25.7% power through board in acoustic condition. 7.3 Mechanical Design Envelope While each design may have unique mechanical volume and height restrictions or implementation requirements, the height, width, and depth constraints typically placed on the Intel 7500 chipset thermal solution are shown in Figure 7-2.
Reference Thermal Solution 2 Figure 7-2. Short Torsional Clip Heatsink Volumetric Envelope for the IOH1 IOH Short Heatsink TIM Die FCBGA + Solder Balls Motherboard 65.00 mm TNB Heatsink IOH Short Heatsink Notes: 1. The dimensions shown above are nominal and post SMT. 7.4 Board-Level Components Keepout Dimensions The location of hole patterns and keepout zones for the reference thermal solution are shown in Figure 7-3 and Figure 7-4. 7.
Reference Thermal Solution 2 Figure 7-3.
Reference Thermal Solution 2 Figure 7-4. Retention Mechanism Component Keepout Zones 7.5.1 Heatsink Orientation Since this solution is based on a unidirectional heatsink, mean airflow direction must be aligned with the direction of the heatsink fins. Figure 7-5.
Reference Thermal Solution 2 7.5.2 Extruded Heatsink Profiles The reference thermal solution uses an extruded heatsink for cooling the IOH. Figure 7-6 shows the heatsink profile. Appendix A lists a supplier for this extruded heatsink. Other heatsinks with similar dimensions and increased thermal performance may be available. Full mechanical drawing of this heatsink is provided in Appendix B. Figure 7-6. Short Torsional Clip Heatsink Extrusion Profile 7.5.
Reference Thermal Solution 2 represents the TIM performance post heatsink assembly while the End of Life value is the predicted TIM performance when the product and TIM reaches the end of its life. The heatsink clip provides enough pressure for the TIM to achieve End of Line thermal resistance of 0.19°C cm2/W and End of Life thermal resistance of 0.39°C cm 2/W. Table 7-2.
Reference Thermal Solution 2 40 Intel® 7500 Chipset Thermal Mechanical Design Guide
Design Recommendations for Solder Joint Reliability 8 Design Recommendations for Solder Joint Reliability Solder Joint Reliability (SJR) remains a major topic of concern in designing systems especially for surface mounted components. Solder ball cracking and fracture is a failure mode associated with overstressing the surface mounted component on the motherboard. The over-stressing typically occurs when the motherboard is subjected to bending deflection.
Design Recommendations for Solder Joint Reliability Figure 8-1. Example of Thick Traces used in a Desktop BGA Package Edge Thick Traces attached to NCTF solder pads NCTF pads are shown in blue 8.2 Shock Strain Guidance A useful metric to compare the impact of design modifications to SJR and assess SJR risk during shock events is strain measurement. This strain measurement, also referred to as shock strain, utilizes strain gages to measure the surface strain of a motherboard.
Design Recommendations for Solder Joint Reliability Table 8-1. Shock Strain Guidance Shock Strain (micro strain, µe) Associated Risk Recommendation / Comments Emin < 2000 Low Solder joint failure is unlikely 2000 < Emin < 2400 Medium Larger sample size and failure analysis is suggested for design validation 2400 < Emin High Solder joint failure is likely, consider design changes to improve reliability Notes: 1.
Design Recommendations for Solder Joint Reliability 44 Intel® 7500 Chipset Thermal Mechanical Design Guide
Thermal Solution Component Suppliers A Thermal Solution Component Suppliers A.
Thermal Solution Component Suppliers Part Alternative Clip Solder-Down Anchor Intel Part Number E12029-001 A13494-007 Supplier (Part Number) Contact Information AVC P/N: A208000345 Ying Ying Zhang (Shenzhen) 86-775-3366-8888 x 63405 ying_zhang@avc.com.cn Kai Chang (Shenzhen/Taiwan) 86-775-3366-8888 x 63588 Kai_chang@avc.com.tw CCI P/N: 334C95740102 Monica Chih (Taiwan) 866-2-29952666, x1131 monica_chih@ccic.com.tw Harry Lin (U.S.A) 714-739-5797 Ackinc@aol.
Thermal Solution Component Suppliers Part Heatsink Attach Clip Solder-Down Anchor Intel Part Number D82345-001 A13494-007 Supplier (Part Number) Contact Information AVC P/N: A208000331 Ying Ying Zhang (Shenzhen) 86-775-3366-8888 x 63405 ying_zhang@avc.com.cn Kai Chang (Shenzhen/Taiwan) 86-775-3366-8888 x 63588 Kai_chang@avc.com.tw CCI P/N: 334C91590101 Monica Chih (Taiwan) 866-2-29952666, x1131 monica_chih@ccic.com.tw Harry Lin (U.S.A) 714-739-5797 Ackinc@aol.
Thermal Solution Component Suppliers 48 Intel® 7500 Chipset Thermal Mechanical Design Guide
Mechanical Drawings B Mechanical Drawings Table B-1 lists the mechanical drawings included in this appendix. Table B-1.
Mechanical Drawings Figure B-1.
Mechanical Drawings Figure B-2.
Mechanical Drawings Figure B-3.
Mechanical Drawings Figure B-4.
Mechanical Drawings Figure B-5.
Mechanical Drawings Figure B-6.
Mechanical Drawings Figure B-7.
Mechanical Drawings Figure B-8.
Mechanical Drawings Figure B-9.
Mechanical Drawings Figure B-10.
Mechanical Drawings 60 Intel® 7500 Chipset Thermal Mechanical Design Guide
